// 例子34

let proto = {w: 30};
let obj = {x: 10};
Object.setPrototypeOf(obj, proto);
console.log(Object.getPrototypeOf(obj)); // {w: 30}
proto.y = 20;
proto.z = 40;
console.log(obj.x); // 10
console.log(obj.y);	// 20
console.log(obj.z);	// 30
console.log(obj.w);	// 40